You don't report the children's K-1, they do, unless it is a loss.
The program will apply the correct tax, it may come up in the summary for the children's return.
Because of the Tax Cuts and Jobs Act, the kiddie tax rate has changed.
"For 2018-2025, the Tax Cuts and Jobs Act (TCJA) revamps the Kiddie Tax rules to tax a portion of an affected child’s or young adult’s unearned income at the rates paid by trusts and estates. Those rates can be as high as 37% or as high as 20% for long-term capital gains and dividends. Before the TCJA, the Kiddie Tax rate equalled the parent’s marginal rate (which for 2017 could be as high as 39.6% or 20% for long-term capital gains and dividends).
The TCJA only changes the Kiddie Tax rate structure. The rest of the Kiddie Tax rules are the same as before. Here’s what you need to know about how the Kiddie Tax can come into play and how much it can cost under the current rules."
https://www.marketwatch.com/story/new-tax-law-makes-dreaded-kiddie-tax-more-expensive-2018-09-24
